This broad-based project explores allergic mechanisms at a number of levels. Antidromic nerve stimulation is an excellent model for exploring the role that endogenous neuropeptides play in disease. We have characterized neurogenic inflammation in rat cutaneous and pulmonary models and have searched for a possible connection to mast cell activation. Our studies indicate that mast cells are not activated by endogenous neuropeptide release and that neuropeptide release does not play a major role in allergic responses. We have contrasted neutrophil derived histamine releasing factor with a number of other mast cell activators, and have found HRA-N to be unique in regards to the spectrum of its activity, the kinetics of mast cell activation, and its biologic characterization. Bronchopulmonary dysplasia can be discriminated from hyaline membrane disease by the relative absence of lactoferrin and lysozyme in tracheal aspirates. This finding suggests that the relative absence of serous cell products predisposes to bronchopulmonary dysplasia (BPD). Bronchopulmonary dysplasia affects 40% of children weighing less than 2 kg. It is estimated that each child with BPD costs society $300,000/year for hospital-related expenses. Our finding of reduced serous cell products in this disease provides the first insight into a pathologic process which may be involved. Moreover, these findings provide a new insight into possible therapeutic interventions.